Definition of mischief :
1. Cause of trouble or vexation; trouble.
2. Harm; damage; esp., disarrangement of order; trouble or vexation caused by human agency or by some living being, intentionally or not; often, calamity, mishap; trivial evil caused by thoughtlessness, or in sport.
3. To do harm to.
whimsicality, slipperiness, wrongdoing, frolicsomeness, impairment, trickery, demureness, wrong, puckishness, trickiness, chicanery, waggishness, devilry, rascal, tomfoolery, high jinks, playfulness, shenanigan, deviltry, blemish, fault, prejudice, good, imp, damage, misbehavior, disadvantage, mischief-making, prankster, sportiveness, prankishness, misdoing, misconduct, shiftiness, balefulness, cutup, loss, roguishness, mischievousness, devil, rogue, chicane, guile, diablerie, devilment, injury, scamp, roguery, rascality, impishness, naughtiness, sedateness, friskiness, hurt, dignity, help, maleficence, wile, harm
crime (part of speech: noun)
evil (part of speech: noun)
detriment, repellency, monstrosity, evil, catastrophe, nefariousness, heinousness, disgrace, bane, badness, sinisterness, repulsiveness, offensiveness, wickedness, abomination, calamitousness, foulness, damnation, reprehensibleness, terribleness, sinfulness, atrocity, ill, hideousness
damage (part of speech: verb)